ALTER TABLE ProximityRadius
ADD RadiusUnits VARCHAR(5) NOT NULL DEFAULT('miles')
GO
ALTER TABLE ProximityRadius
ADD FromRadiusFeet AS (CASE WHEN RadiusUnits = 'miles' THEN FromRadius * 5280 ELSE FromRadius END),
	ToRadiusFeet AS (CASE WHEN RadiusUnits = 'miles' THEN ToRadius * 5280 ELSE ToRadius END)
GO	